Project description:This study was conducted by DNA pulldown assay using 4 Biotin-labeled Timeless promoters with different lengths and identified by high resolution mass spectrometry.
Project description:Lung adenocarcinoma (LUAD) has a poor prognosis. Circadian genes such as TIMELESS have been associated with several pathologies, including cancer. The expression of TIMELESS and the relationship between TIMELESS, infiltration of tumors and prognosis in LUAD requires further investigation. In this study, we investigated the expression of TIMELESS and its association with survival across several types of human cancer using data from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression Program. Noncoding RNAs (ncRNAs) regulating overexpression of TIMELESS in lung adenocarcinoma (LUAD) were explored with expression, correlation, and survival analyses. Immune cell infiltration and biomarkers were analyzed between different TIMELESS expression levels. The relationship between TIMELESS expression and immunophenoscores, which were used to predict response to immunotherapy, was evaluated. TIMELESS was identified as a potential oncogene in LUAD. NcRNA analysis showed MIR4435-2HG/hsa-miR-1-3p may interact with TIMELESS in a competitive endogenous RNA network in LUAD tumor tissues. Most immune cells were significantly decreased in TCGA LUAD tumor tissues with high TIMELESS expression except for CD4+T cells and Th2 cells. TIMELESS expression in LUAD tumor tissues was significantly negatively correlated with neutrophil biomarkers, dendritic cell biomarkers (HLA-DPB1, HLA-DQB1, HLA-DRA, HLA-DPA1, CD1C) and an immunophenoscore that predicted outcomes associated with the use of immune checkpoint inhibitors. These findings imply that ncRNAs-mediated TIMELESS overexpression in LUAD tumor tissues correlated with poor prognosis, reduced immune cell infiltration in the tumor microenvironment, and poor response to immune checkpoint inhibitors.
Project description:BackgroundGremlin, a member of the Dan family of BMP antagonists, is a glycosylated extracellular protein. Previously Gremlin has been shown to play a role in dorsal-ventral patterning, in tissue remodeling, and recently in angiogenesis. Evidence has previously been presented showing both over- and under-expression of Gremlin in different tumor tissues. Here, we sought to quantify expression of Gremlin in cancers of the lung and performed in vitro experiments to check whether Gremlin promotes cell growth and proliferation.Methodology/principal findingsExpression of Gremlin in 161 matched tumor and normal lung cancer specimens is quantified by quantitative real-time PCR and protein level is measured by immunohistochemistry. GREM1 was transfected into lung fibroblast and epithelial cell lines to assess the impact of overexpression of Gremlin in vitro.ResultsLung adenocarcinoma but not squamous cell carcinoma shows a significant increase in Gremlin expression by mRNA and protein level. Lung fibroblast and epithelial cell lines transfected with GREM1 show significantly increased cell proliferation.Conclusions/significanceOur data suggest that Gremlin acts in an oncogenic manner in lung adenocarcinoma and could hold promise as a new diagnostic marker or potential therapeutic target in lung AD or general thoracic malignancies.
Project description:Syndecan-4 (SDC4) is a cell-surface proteoglycan associated with cell adhesion, motility, and intracellular signaling. Here, we present that SDC4 functions as a positive regulator of the transforming growth factor (TGF)-?1-induced epithelial to mesenchymal transition (EMT) via Snail in lung adenocarcinoma, A549 cells. TGF-?1 up-regulated the expression of SDC4, accompanied by the induction of EMT. Wound-healing and transwell chemotaxis assay revealed that SDC4 promoted cell migration and invasion. SDC4 knockdown recovered the E-cadherin and decreased vimentin and Snail expression in EMT-induced A549 cells. However, depletion of SDC4 resulted in little change of the Slug protein expression and mesenchymal cell morphology induced by TGF-?1. The double knockdown of SDC-4 and Slug was required for reversal of epithelial morphology; it did not occur from the SDC4 single knockdown. These findings suggest that Snail is a transcriptional factor downstream of SDC4, and SDC4 regulates TGF-?1-induced EMT by cooperating with Slug. Our data provide a novel insight into cellular mechanisms, whereby the cell-surface proteoglycan modulated TGF-?1-induced EMT in lung adenocarcinoma, A549 cells.
Project description:BackgroundThere is evidence that DNA methylation play major roles in lung cancer. In our previously study, C3 or f21 , also referred to as XXYLT1, rs2131877 polymorphism is associated with a reduced risk of lung adenocarcinoma. So, we explored the role of XXYLT1 methylation in lung adenocarcinoma.MethodsThis study was conducted in 2 steps. In the first step, we recruited 15 patients with lung adenocarcinoma. Cancer tissues and para-carcinoma tissues were obtained from each of the patients. In the second step, 150 patients with lung adenocarcinom were enrolled, and cancer and normal lung tissue were obtained from each patients, respectively. The expression levels of XXYLT1 mRNA were determined, the deoxyribonucleic acid methylation status was analyzed by MassARRAY Spectrometry. The methylation data of individual units were generated by EpiTyper v1.0.5 software.ResultsThe XXYLT1 mRNA expression was significantly lower in cancer tissues than in para-carcinoma and normal lung tissues. Meanwhile, the methylation rates of three CpG units (CpG_23, CpG_25, and CpG_60.61.62.63.64.65) within the XXYLT1 gene were higher in cancer tissues compared to the para-carcinoma and the normal lung tissues. This difference was particularly significant in male patients.ConclusionsOur results suggested that methylation of XXYLT1 may have significance in the pathogenesis of lung adenocarcinoma.
Project description:By transducing an apoptotic signal in immune effector cells, Fas has been directly implicated in the control of immunological activity. Expression and functional results, however, have also suggested a role for Fas in regulating cell turnover in specific epithelial populations. To characterize factors responsible for Fas expression in epithelial cells, approximately 3 kb of the 5' flanking region of the mouse Fas gene was isolated. By rapid amplification of cDNA ends and primer extension, transcriptional start sites were identified within 50 bp upstream of the translation start site. Transient transfection of promoter-luciferase constructs in a mouse lung epithelial cell line, MLE-15, localized promoter activity to the first 77 bp of upstream sequence. By using a 60 bp DNA probe (-18 to -77) in electrophoretic mobility-shift assays, three shifted complexes were found. Incubation with excess cold Sp1 oligonucleotide or an anti-Sp3 antibody inhibited complex formation. Site-directed mutagenesis of the Sp1 site resulted in 60-70% loss of promoter activity. In Drosophila SL-2 cells, promoter activity was markedly increased by co-transfection of an Sp3 expression construct. These results show that the Sp3 protein is involved in regulating Fas gene expression in lung epithelial cells.
Project description:Tumor-associated inflammation plays a critical role in facilitating tumor growth, invasion and metastasis. Our previous study showed Aflatoxin G1 (AFG1) could induce lung adenocarcinoma in mice. Chronic lung inflammation associated with superoxide dismutase (SOD)-2 upregulation was found in the lung carcinogenesis. However, it is unclear whether tumor-associated inflammation mediates SOD-2 to contribute to cell invasion in AFG1-induced lung adenocarcinoma. Here, we found increased SOD-2 expression associated with vimentin, α-SMA, Twist1, and MMP upregulation in AFG1-induced lung adenocarcinoma. Tumor-associated inflammatory microenvironment was also elicited, which may be related to SOD-2 upregulation and EMT in cancer cells. To mimic an AFG1-induced tumor-associated inflammatory microenvironment in vitro, we treated A549 cells and human macrophage THP-1 (MΦ-THP-1) cells with AFG1, TNF-α and/or IL-6 respectively. We found AFG1 did not promote SOD-2 expression and EMT in cancer cells, but enhanced TNF-α and SOD-2 expression in MΦ-THP-1 cells. Furthermore, TNF-α could upregulate SOD-2 expression in A549 cells through NF-κB pathway. Blocking of SOD-2 by siRNA partly inhibited TNF-α-mediated E-cadherin and vimentin alteration, and reversed EMT and cell migration in A549 cells. Thus, we suggest that tumor-associated inflammation mediates SOD-2 upregulation through NF-κB pathway, which may contribute to EMT and cell migration in AFG1-induced lung adenocarcinoma.
Project description:Hyperactive EGF receptor (EGFR) and mutant p53 are common genetic abnormalities driving the progression of non-small cell lung cancer (NSCLC), the leading cause of cancer deaths in the world. The Drosophila gene Dachshund (Dac) was originally cloned as an inhibitor of hyperactive EGFR alleles. Given the importance of EGFR signaling in lung cancer etiology, we examined the role of DACH1 expression in lung cancer development. DACH1 protein and mRNA expression was reduced in human NSCLC. Reexpression of DACH1 reduced NSCLC colony formation and tumor growth in vivo via p53. Endogenous DACH1 colocalized with p53 in a nuclear, extranucleolar location, and shared occupancy of -15% of p53-bound genes in ChIP sequencing. The C-terminus of DACH1 was necessary for direct p53 binding, contributing to the inhibition of colony formation and cell-cycle arrest. Expression of the stem cell factor SOX2 was repressed by DACH1, and SOX2 expression was inversely correlated with DACH1 in NSCLC. We conclude that DACH1 binds p53 to inhibit NSCLC cellular growth.